PRIOR CONCURRENT THERAPY: Biologic therapy: At least 28 days since prior biologic therapy Chemotherapy: No more than 3 prior chemotherapy regimens, including no more than 2 cytotoxic regimens AND 1 high-dose cytotoxic regimen as part of stem cell transplantation Endocrine therapy: At least 28 days since prior endocrine therapy Radiotherapy: At least 28 days since prior radiotherapy (except for focal radiotherapy for symptom control) Surgery: Not specified